The production methods of medical catheters, especially urinary catheters, have been seen as complex processes where the intermediate products are subject to a number of different production steps before being ready for packaging, shipping and for the use by the consumer.
Urinary catheters usually comprise a number of technical features which characterize the catheters. These features are: a catheter tube, a catheter tip, drainage eyes and a connector. Each one of these technical features usually require its distinctive production step in order to make the feature a part of the finished catheter.
An example of these distinctive production steps may be seen in the production of a well known type of intermittent catheter, such as the Easicath catheter by Coloplast A/S or the LoFric catheter by Astratech AB. The catheter tube is extruded in a thermoplastic material, having a predetermined diameter and a predetermined length which vary on basis of the user groups these catheters are supposed to serve. Subsequently, the insertable proximal end of the catheter tube is provided with an insertable tip which closes the proximal end of the catheter tube and provides an low impact tip which reduces the risk of causing damage to the mucosa of the urinary channel during the insertion of the catheter. After the tipping of the catheter, one or more drainage eyes are provided on the side walls of the tubing close to the proximal end of the catheter tube in order to provide drainage from the urine bladder subsequent to the insertion of the catheter. Finally, a connector is attached to the distal end of the catheter tube to provide a structure for allowing the user to grip and control the catheter during insertion and retraction and also to provide a connector for a urine bag if necessary. This type of catheter may, subsequently to the aforementioned production steps, be subjected to further production steps in order provide surface treatment, sterilization, etc.
This method of producing a catheter may be seen as time consuming, complex and costly as the catheter is subjected to a number of different production steps, where each step requires different resources, such as a specific machine, man hours for operating the machine or machine time for providing the technical feature. And if any one of these production steps fails, the resulting catheter has to be discarded.
WO 2005/046959 discloses a method for the injection moulding of soft needle catheters comprising a hub and a soft flexible part. The disclosed method provides a catheter that is designed to be provided as a sleeve surrounding an intravenous injection needle, which means that the proximal end of the catheter is open for the insertion of an IV injection needle along its longitudinal axis.
US 2005/033237 discloses a method for injection moulding intravenous needle catheters having a catheter tube and a hub, where the catheter tube is open in its proximal end so that an intravenous injection needle may protrude through the proximal end of the catheter.
Previously, the injection moulding of a catheter assembly has been affected by the fact that the core pin, which forms the inner lumen of the catheter tube, has been stabilized by anchoring the free end of the core pin on the outside the injection moulding cavity. This means that the free end of the core pin extends outside the elongated cavity into an anchoring mechanism that is located past the mould, so that the pin will maintain its stability during the injection of the liquid catheter material into the mould. Thus, catheters which are moulded in such a way have an open tip. Such catheters are commonly used for intravenous applications, where the catheter surrounds a syringe needle and where the syringe needle is removed subsequent to the insertion of the needle and the catheter. However, such a method is not well suited for the moulding of urinary catheters and the use of this method would mean that subsequent to the solidification of the catheter material, and subsequent to the removal of the catheter from the mould, the tip has to be formed. Hence there is a need for an improved method of injection moulding catheters which have a tip that closes off the insertable end of the catheter tube.